// SPDX-License-Identifier: GPL-2.0-only
/*
 * Test cases for the drm_mm range manager
 *
 * Copyright (c) 2022 Arthur Grillo <arthur.grillo@usp.br>
 */

#include <kunit/test.h>

#include <linux/prime_numbers.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/vmalloc.h>
#include <linux/ktime.h>

#include <drm/drm_mm.h>
#include <drm/drm_print.h>

#include "../lib/drm_random.h"

enum {
        BEST,
        BOTTOMUP,
        TOPDOWN,
        EVICT,
};

static const struct insert_mode {
        const char *name;
        enum drm_mm_insert_mode mode;
} insert_modes[] = {
        [BEST] = { "best", DRM_MM_INSERT_BEST },
        [BOTTOMUP] = { "bottom-up", DRM_MM_INSERT_LOW },
        [TOPDOWN] = { "top-down", DRM_MM_INSERT_HIGH },
        [EVICT] = { "evict", DRM_MM_INSERT_EVICT },
        {}
};

static bool assert_no_holes(struct kunit *test, const struct drm_mm *mm)
{
        struct drm_mm_node *hole;
        u64 hole_start, __always_unused hole_end;
        unsigned long count;

        count = 0;
        drm_mm_for_each_hole(hole, mm, hole_start, hole_end)
                count++;
        if (count) {
                KUNIT_FAIL(test,
                           "Expected to find no holes (after reserve), found %lu instead\n", count);
                return false;
        }

        drm_mm_for_each_node(hole, mm) {
                if (drm_mm_hole_follows(hole)) {
                        KUNIT_FAIL(test, "Hole follows node, expected none!\n");
                        return false;
                }
        }

        return true;
}

static bool assert_one_hole(struct kunit *test, const struct drm_mm *mm, u64 start, u64 end)
{
        struct drm_mm_node *hole;
        u64 hole_start, hole_end;
        unsigned long count;
        bool ok = true;

        if (end <= start)
                return true;

        count = 0;
        drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
                if (start != hole_start || end != hole_end) {
                        if (ok)
                                KUNIT_FAIL(test,
                                           "empty mm has incorrect hole, found (%llx, %llx), expect (%llx, %llx)\n",
                                           hole_start, hole_end, start, end);
                        ok = false;
                }
                count++;
        }
        if (count != 1) {
                KUNIT_FAIL(test, "Expected to find one hole, found %lu instead\n", count);
                ok = false;
        }

        return ok;
}

static u64 misalignment(struct drm_mm_node *node, u64 alignment)
{
        u64 rem;

        if (!alignment)
                return 0;

        div64_u64_rem(node->start, alignment, &rem);
        return rem;
}

static bool assert_node(struct kunit *test, struct drm_mm_node *node, struct drm_mm *mm,
                        u64 size, u64 alignment, unsigned long color)
{
        bool ok = true;

        if (!drm_mm_node_allocated(node) || node->mm != mm) {
                KUNIT_FAIL(test, "node not allocated\n");
                ok = false;
        }

        if (node->size != size) {
                KUNIT_FAIL(test, "node has wrong size, found %llu, expected %llu\n",
                           node->size, size);
                ok = false;
        }

        if (misalignment(node, alignment)) {
                KUNIT_FAIL(test,
                           "node is misaligned, start %llx rem %llu, expected alignment %llu\n",
                           node->start, misalignment(node, alignment), alignment);
                ok = false;
        }

        if (node->color != color) {
                KUNIT_FAIL(test, "node has wrong color, found %lu, expected %lu\n",
                           node->color, color);
                ok = false;
        }

        return ok;
}

static void drm_test_mm_init(struct kunit *test)
{
        const unsigned int size = 4096;
        struct drm_mm mm;
        struct drm_mm_node tmp;

        /* Start with some simple checks on initialising the struct drm_mm */
        memset(&mm, 0, sizeof(mm));
        KUNIT_ASSERT_FALSE_MSG(test, drm_mm_initialized(&mm),
                               "zeroed mm claims to be initialized\n");

        memset(&mm, 0xff, sizeof(mm));
        drm_mm_init(&mm, 0, size);
        if (!drm_mm_initialized(&mm)) {
                KUNIT_FAIL(test, "mm claims not to be initialized\n");
                goto out;
        }

        if (!drm_mm_clean(&mm)) {
                KUNIT_FAIL(test, "mm not empty on creation\n");
                goto out;
        }

        /* After creation, it should all be one massive hole */
        if (!assert_one_hole(test, &mm, 0, size)) {
                KUNIT_FAIL(test, "mm not one hole on creation");
                goto out;
        }

        memset(&tmp, 0, sizeof(tmp));
        tmp.start = 0;
        tmp.size = size;
        if (drm_mm_reserve_node(&mm, &tmp)) {
                KUNIT_FAIL(test, "failed to reserve whole drm_mm\n");
                goto out;
        }

        /* After filling the range entirely, there should be no holes */
        if (!assert_no_holes(test, &mm)) {
                KUNIT_FAIL(test, "mm has holes when filled");
                goto out;
        }

        /* And then after emptying it again, the massive hole should be back */
        drm_mm_remove_node(&tmp);
        if (!assert_one_hole(test, &mm, 0, size)) {
                KUNIT_FAIL(test, "mm does not have single hole after emptying");
                goto out;
        }

out:
        drm_mm_takedown(&mm);
}

static void drm_test_mm_debug(struct kunit *test)
{
        struct drm_printer p = drm_dbg_printer(NULL, DRM_UT_CORE, test->name);
        struct drm_mm mm;
        struct drm_mm_node nodes[2];

        /* Create a small drm_mm with a couple of nodes and a few holes, and
         * check that the debug iterator doesn't explode over a trivial drm_mm.
         */
        drm_mm_init(&mm, 0, 4096);

        memset(nodes, 0, sizeof(nodes));
        nodes[0].start = 512;
        nodes[0].size = 1024;
        KUNIT_ASSERT_FALSE_MSG(test, drm_mm_reserve_node(&mm, &nodes[0]),
                               "failed to reserve node[0] {start=%lld, size=%lld)\n",
                               nodes[0].start, nodes[0].size);

        nodes[1].size = 1024;
        nodes[1].start = 4096 - 512 - nodes[1].size;
        KUNIT_ASSERT_FALSE_MSG(test, drm_mm_reserve_node(&mm, &nodes[1]),
                               "failed to reserve node[0] {start=%lld, size=%lld)\n",
                               nodes[0].start, nodes[0].size);

        drm_mm_print(&mm, &p);
        KUNIT_SUCCEED(test);
}

static bool expect_insert(struct kunit *test, struct drm_mm *mm,
                          struct drm_mm_node *node, u64 size, u64 alignment, unsigned long color,
                        const struct insert_mode *mode)
{
        int err;

        err = drm_mm_insert_node_generic(mm, node,
                                         size, alignment, color,
                                         mode->mode);
        if (err) {
                KUNIT_FAIL(test,
                           "insert (size=%llu, alignment=%llu, color=%lu, mode=%s) failed with err=%d\n",
                           size, alignment, color, mode->name, err);
                return false;
        }

        if (!assert_node(test, node, mm, size, alignment, color)) {
                drm_mm_remove_node(node);
                return false;
        }

        return true;
}

static void drm_test_mm_align_pot(struct kunit *test, int max)
{
        struct drm_mm mm;
        struct drm_mm_node *node, *next;
        int bit;

        /* Check that we can align to the full u64 address space */

        drm_mm_init(&mm, 1, U64_MAX - 2);

        for (bit = max - 1; bit; bit--) {
                u64 align, size;

                node = kzalloc_obj(*node);
                if (!node) {
                        KUNIT_FAIL(test, "failed to allocate node");
                        goto out;
                }

                align = BIT_ULL(bit);
                size = BIT_ULL(bit - 1) + 1;
                if (!expect_insert(test, &mm, node, size, align, bit, &insert_modes[0])) {
                        KUNIT_FAIL(test, "insert failed with alignment=%llx [%d]", align, bit);
                        goto out;
                }

                cond_resched();
        }

out:
        drm_mm_for_each_node_safe(node, next, &mm) {
                drm_mm_remove_node(node);
                kfree(node);
        }
        drm_mm_takedown(&mm);
}

static void drm_test_mm_align32(struct kunit *test)
{
        drm_test_mm_align_pot(test, 32);
}

static void drm_test_mm_align64(struct kunit *test)
{
        drm_test_mm_align_pot(test, 64);
}

static void drm_test_mm_once(struct kunit *test, unsigned int mode)
{
        struct drm_mm mm;
        struct drm_mm_node rsvd_lo, rsvd_hi, node;

        drm_mm_init(&mm, 0, 7);

        memset(&rsvd_lo, 0, sizeof(rsvd_lo));
        rsvd_lo.start = 1;
        rsvd_lo.size = 1;
        if (drm_mm_reserve_node(&mm, &rsvd_lo)) {
                KUNIT_FAIL(test, "Could not reserve low node\n");
                goto err;
        }

        memset(&rsvd_hi, 0, sizeof(rsvd_hi));
        rsvd_hi.start = 5;
        rsvd_hi.size = 1;
        if (drm_mm_reserve_node(&mm, &rsvd_hi)) {
                KUNIT_FAIL(test, "Could not reserve low node\n");
                goto err_lo;
        }

        if (!drm_mm_hole_follows(&rsvd_lo) || !drm_mm_hole_follows(&rsvd_hi)) {
                KUNIT_FAIL(test, "Expected a hole after lo and high nodes!\n");
                goto err_hi;
        }

        memset(&node, 0, sizeof(node));
        if (drm_mm_insert_node_generic(&mm, &node, 2, 0, 0, mode)) {
                KUNIT_FAIL(test, "Could not insert the node into the available hole!\n");
                goto err_hi;
        }

        drm_mm_remove_node(&node);
err_hi:
        drm_mm_remove_node(&rsvd_hi);
err_lo:
        drm_mm_remove_node(&rsvd_lo);
err:
        drm_mm_takedown(&mm);
}

static void drm_test_mm_lowest(struct kunit *test)
{
        drm_test_mm_once(test, DRM_MM_INSERT_LOW);
}

static void drm_test_mm_highest(struct kunit *test)
{
        drm_test_mm_once(test, DRM_MM_INSERT_HIGH);
}

static struct kunit_case drm_mm_tests[] = {
        KUNIT_CASE(drm_test_mm_init),
        KUNIT_CASE(drm_test_mm_debug),
        KUNIT_CASE(drm_test_mm_align32),
        KUNIT_CASE(drm_test_mm_align64),
        KUNIT_CASE(drm_test_mm_lowest),
        KUNIT_CASE(drm_test_mm_highest),
        {}
};

static struct kunit_suite drm_mm_test_suite = {
        .name = "drm_mm",
        .test_cases = drm_mm_tests,
};

kunit_test_suite(drm_mm_test_suite);

MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Test cases for the drm_mm range manager");
MODULE_LICENSE("GPL");